In general, a frame intake of a gas cutting apparatus may configured so that cutting oxygen is injected through a central portion thereof, and preheating frame for preheating a workpiece is formed around the cutting oxygen. Here, the preheating flame ignites a mixed gas that is generated by mixing gaseous oxygen with fuel gas, which are supplied into the gas cutting apparatus.
A general gas cutting apparatus may be classified into a torch mixing type cutting apparatus in which oxygen and fuel gases are mixed with to generate preheating flame and a nozzle (flame outlet) mixing type cutting apparatus. In detail, the gas cutting apparatus may be classified into a first type cutting apparatus and a third type cutting apparatus according to the KS B4601 standard.
Here, in the first type cutting apparatus according to the KS B4601 standard that is the torch mixing type cutting apparatus, oxygen and fuel gas are mixed with each other within a valve bundle including a handle, and then, the mixed gas is supplied into a flame outlet.
In case of the torch mixing type gas cutting apparatus, since flame is introduced into a valve bundle in which a mixed gas is generated when backfire occurs, the backfire may occur in use. Also, if the backfire occurs, the valve bundle may be heated by the flame introduced into the valve bundle to allow a worker to be burnt or to reduce a lifecycle of the valve bundle. In addition, a pressure within the valve bundle may increase to damage a fuel gas tube or fuel gas container.
On the other hand, in the third type cutting apparatus according to the KS B4601 standard that is the nozzle mixing type cutting apparatus, oxygen and fuel gases, which are supplied through the valve bundle reach a nozzle along separate paths and then are mixed with each other in the nozzle to generate a mixed gas.
The nozzle nixing type gas cutting apparatus may have low possibility in backfire. However, it is difficult to stably supply the fuel gas that has a relatively low pressure when compared to that of the oxygen. As a result, it may take a long time to preheat a workpiece. To compensate the above-described problems, if the fuel gas increases in pressure, the backfire may occur to increase in possibility of an accident occurrence.